Normalizes a number to within a desired range

normalize.php

<?php

/**
 * Normalizes a number to within a desired range
 *
 * @param int|float $input     Number to be normalized
 * @param int|float $inputMin  Lowest number that $input can possibly be
 * @param int|float $inputMax  Highest number that $input can possibly be
 * @param int|float $outputMin Lower range for desired output
 * @param int|float $outputMax Upper range for desired output
 * @param int       $precision Optional number of decimal digits to round to
 *
 * @return int|float Normalized number
 */
function normalize($input, $inputMin, $inputMax, $outputMin, $outputMax, $precision = false) {

	// Determine ranges
	$inputRange  = $inputMax  - $inputMin;
	$outputRange = $outputMax - $outputMin;

	// Determine result within desired range
	$ratio  = $inputRange / $outputRange;
	$output = $input / $ratio + $inputMin;

	// Round?
	if ($precision !== false && $precision >= 0)
		$output = round($output, $precision);

	// If number has no decimals, convert to int
	if (intval($output) == $output)
		$output = intval($output);

	return $output;

}